1) Uninstall the 'cleaner' using the manufacture's instructions. Those are notorious for causing new problems.
2) Stop worrying about the cache. Usually cache makes your machine run faster.
3) Reinstall or restore to an external USB 3 SSD (assuming you have a 2012-2019 21.5" iMac with a 5400rpm HDD).
4) If an external SSD isn't an option uninstall MS office, especially One Drive. Those poor 5400rpm drives can only just keep up with MacOS. When you run 3rd party auto-updaters, authenticators, and file-syncing in the background they start to become bottlenecks.
Optional: Run Etrecheck and post the results. (Use the 'additional text' post button next to 'insert image'). There may be other issues.